[netcdf-java] Reading an OPeNDAP URL using a constraint expression.

• To: netcdf-java@xxxxxxxxxxxxxxxx
• Subject: [netcdf-java] Reading an OPeNDAP URL using a constraint expression.
• From: Brian Schlining <bschlining@xxxxxxxxx>
• Date: Thu, 10 May 2012 10:14:38 -0700

Hi All,

I'm trying to read an opendap url using a contraint expression in
NetCDF-Java. I checked out the thredds source code and built the latest
version (4.3.9-SNAPSHOT). It *sort of* works but I'm confused about reading
data. Here's my example:

% Note I'm testing this in Matlab. so the code may look like pseudo code.
nc = ucar.nc2.dataset.NetcdfDataset.openDataset('
http://geoport.whoi.edu/thredds/dodsC/examples/OS_M1_20081008_TS.nc?PSAL[0:1:100][0:1:0][0:1:0][0:1:0]'
);
vs = nc.getVariables;
psal = vs.get(0)

psal =

   float PSAL(TIME=101, DEPTH=1, LATITUDE=1, LONGITUDE=1);
     :_CoordinateAxes = "TIME DEPTH LATITUDE LONGITUDE ";
     :missing_value = -1.0E34f; // float
     :_FillValue = -1.0E34f; // float
     :long_name = "Hourly sea_water_salinity";
     :units = " ";
     :standard_name = "sea_water_salinity";
     :uncertainty = "0.02";
     :valid_min = "30";
     :valid_max = "36";
     :cell_methods = "time: mean";
     :history = "From m1_ctd0001_20081008_original";


% SO the above code worked as expected and everything looks good.
% However when I read the data like so:
array = psal.read()
psalData = array.copyToNDJavaArray();
size(psalData)

ans =

        9043          11

 ???? I was expecting an array with a size of 101 by 1 as defined in the
contraint expression, but it returns the full 9043 by 11 psal dsdata set.
Is there a different way I'm supposed to read the data when a constraint
expression is used? Any guidance on this would be appreciated.

Cheers

-- B
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Brian Schlining
bschlining@xxxxxxxxx
Monterey Bay Aquarium Research Institute

• Follow-Ups:
  • Re: [netcdf-java] Reading an OPeNDAP URL using a constraint expression.
    • From: John Caron